
//let arr = [10,20,30]
//console.log(arr[2])
let arr = [11,22,33]
for(let i in arr){
    console.log(i,arr[i])
}

let stu = {id:10,name:'李四',age:18,addr:'河南省郑州'}
for(let k in stu){
    console.log(k,stu[k])
}


let ns = [10,20,30,40,50]
for(let i=0;i<ns.length;i++){
    console.log(ns[i])
}

for(let i=ns.length-1;i>=0;--i){
    console.log(ns[i])
}

for(let n in ns){
    console.log(ns[n],ns[ns.length - 1 - n])
}
